Method for the co-extrusion of a complex rubber profiled element intended for the manufacture of tires

Abstract

A method for the co-extrusion of a rubber profiled element consists in extruding and profiling the various rubbery materials of the co-extruded profiled element over a given co-extrusion width and in a longitudinal direction of co-extrusion perpendicular to the transverse plane (PT). The method comprises the following succession of steps consisting in: a) extruding a first material, this being performed discontinuously, b) first profiling of the first material, performed discontinuously, c) extruding a second material, this being performed discontinuously, d) profiling the first and second materials, creating at least one longitudinal groove (26) in the profiled element (20), and, jointly, at least an extruding of a third material next to each longitudinal groove (26) created in the profiled element (20), and e) final profiling of the first, second and third materials to a final profile (P74) exhibiting no discontinuity across the co-extrusion width (L50).

1 .- 12 . (canceled) 
     
     
         13 . A method for co-extrusion of a complex rubber profiled element intended for the manufacture of a tire, the complex profiled element comprising along its height a first sublayer layer of a first rubbery material and a second tread layer of a second rubbery material superposed on the sublayer, the first sublayer layer and the second tread layer having at least one discontinuity in the width of the complex profiled element that extends in a transverse direction so that at least one insert of a third rubbery material is inserted into the at least one discontinuity of the first sublayer layer and the second tread layer at the time of co-extrusion, the method consisting of extruding and profiling the first, second and third rubbery materials over a given co-extrusion width and in a longitudinal direction of co-extrusion perpendicular to a transverse plane of the co-extruded profiled element, the method comprising the following succession of steps:
 (a) extruding the first rubbery material discontinuously across the co-extrusion width;   (b) first profiling the first rubbery material discontinuously across the co-extrusion width;   (c) extruding the second rubbery material discontinuously across the co-extrusion width in such a way as to superpose the second rubbery material on the first rubbery material;   (d) profiling the first and second rubbery materials to a profile exhibiting no discontinuity across the co-extrusion width, at least one longitudinal groove being created in the profiled element, the profiling of the first and second rubbery materials being performed jointly with at least an extruding of the third rubbery material next to the at least one longitudinal groove created in the profiled element; and   (e) final profiling of the first, second and third rubbery materials to a final profile exhibiting no discontinuity across the co-extrusion width, a final shape thereof being given to the at least one longitudinal groove created in the profiled element in step (d) and situated transversely next to at least one insert originating from an extrusion of the third rubbery material according to step (d).   
     
     
         14 . The method for co-extrusion of a complex rubber profiled element according to  claim 13 , wherein, with the third rubbery material being extruded next to the at least one longitudinal groove according to an outlet cross-section of a determined shape, a band of non-zero height and width of the first rubbery material is extruded upstream of each third rubbery material outlet section and underneath each third rubbery material outlet section. 
     
     
         15 . The method for co-extrusion of a complex rubber profiled element according to  claim 14 , wherein a height of the first rubbery material extruded upstream of each third rubbery material outlet section is progressively reduced. 
     
     
         16 . The method for co-extrusion of a complex rubber profiled element according to  claim 15 , wherein the height of the first rubbery material extruded upstream of each third rubbery material outlet section is reduced in stages. 
     
     
         17 . The method for co-extrusion of a complex rubber profiled element according to  claim 13 , wherein, during step (d), the third rubbery material is extruded according to an outlet cross-section in a transverse plane containing at least one triangular subsection and in such a way that the at least one triangular subsection constitutes one side wall of the at least one longitudinal groove created in the profiled element. 
     
     
         18 . The method for co-extrusion of a complex rubber profiled element according to  claim 17 , wherein, during step (d), the third rubbery material is extruded according to an outlet cross-section in a transverse plane containing two triangular subsections distant from one another in the transverse direction of extrusion and in such a way that the third rubbery material extruded by the two triangular subsections constitutes two side walls of the at least one longitudinal groove created in the profiled element. 
     
     
         19 . The method for co-extrusion of a complex rubber profiled element according to  claim 18 , wherein, at the same time as performing step (c), a part of the flow of the second material is diverted toward at least one discontinuity created during steps (a), (b), and (c) in the superposed first and second rubbery materials in such a way that the diverted flow of the second rubbery material arrives between the two triangular subsections of the third rubbery material outlet in the transverse direction of extrusion. 
     
     
         20 . The method for co-extrusion of a complex rubber profiled element according to  claim 13 , wherein, during steps (a) through (c), three discontinuities are created in the first and second rubbery materials in the transverse direction of extrusion. 
     
     
         21 . The method for co-extrusion of a complex rubber profiled element according to  claim 13 , wherein a longitudinal direction of co-extrusion extends radially around a central axis. 
     
     
         22 . The method for co-extrusion of a complex rubber profiled element according to  claim 13 , wherein the extruding and profiling steps are performed between a roller and an extrusion head, comprising a lower wall of cylindrical profile collaborating with an exterior wall of the roller. 
     
     
         23 . A complex rubber profiled element obtained from the method according to  claim 13 . 
     
     
         24 . A tire manufactured from a complex rubber profiled element according to  claim 23 .